Evan, you started working with diamonds during your undergraduate studies and have remained focused on this research topic to this day. What fascinates you about diamonds?
I find it fascinating that diamond can be used for a lot more than just jewellery, with applications ranging from cutting, grinding, and forming tools to more advanced technologies such as high-power electronic devices and night-vision devices. It was the latter of these that first sparked my interest in the material during the third-year project of my undergraduate studies at University College London.
What are diamonds used for in microproduction technology?
Diamond has a remarkable set of properties that make it ideally suited to a subset of microsystems-based applications.
For example, it’s one of the stiffest materials, if not the stiffest material, known to exist, meaning that acoustic waves propagate through it incredibly fast. This allows researchers to create miniaturised mechanical resonators that operate at much higher frequencies than those made from other materials. These diamond resonators can find use in fundamental physics applications, such as demonstrating the applicability of quantum mechanics to macroscopic objects. They also have practical applications, such as radio-frequency filtering to segregate signals sent via communication devices, including WiFi, 5G, and many others.
Regarding its optical properties, diamond has a high refractive index and a broad transmission window, which means it’s well suited for photonic circuits that use light rather than electrons for information processing. By adding small amounts of elements such as nitrogen and silicon to the diamond lattice, defects called colour vacancy centres can also be created. Such colour centres can be exploited to detect minuscule changes in the surrounding environment and act as the building blocks of quantum computers. This makes diamond highly interesting for optics and photonics research at Leibniz University Hannover and within the PhoenixD consortium.
Finally, there is also a growing trend to miniaturise high-power III-V semiconductor devices to pack more into a given volume while handling greater currents. This generates heat that reduces performance and shortens device lifetime. As diamond possesses the highest thermal conductivity of any bulk material, there’s a lot of interest in using thin diamond layers in direct contact with these devices to draw away heat and enable further miniaturisation.
Since September 2023, you have been building up the “Diamond Research” group at IMPT. What are you currently working on?
At the moment we’re trying to establish the processes required for routine use of the diamond that we grow.
One of the biggest issues with diamond films is polishing away the often-significant roughness left after growth. At my last position, we worked on using a process called chemical mechanical polishing (CMP) using silica, essentially nano-scale sand, to do this. The technique works but it’s very slow, so here at the IMPT we’re working on alternative polishing techniques, while also trying to speed up the CMP process itself. That’s my main lab work at the moment.
Outside of the lab, I’m doing more direct management of undergraduate and PhD students, funding acquisition, and participating in collaborative meetings.
Imagine you look back on your work at the IMPT in 10 years’ time: What would you like to have achieved?
I would like the IMPT to have a well-established diamond group that’s known for doing solid work on the use of diamond within microsystems. The IMPT possesses a suite of cleanroom tools that makes it well suited to this task, with further tools on the way, giving it the potential to be a significant player in diamond-based device fabrication. With these tools and processes, the institute will then be able to fabricate advanced diamond devices that target many of the applications previously mentioned, and act as a fabrication partner for other diamond groups that have novel applications and methods for characterisation, but not necessarily the means by which to construct the devices.
What distinguishes academic work in Germany from the UK? What differences have surprised you?
Here at the IMPT, I’ve noticed that the job seems to be a lot less compartmentalised. In the UK as a PhD student and then a postdoc you have tasks that you do and that fall within your remit. At the IMPT, research associates (PhD students) and postdocs seem to do a lot more and contribute to a wider range of tasks, e.g. funding acquisition, technical support, day-to-day running of the cleanroom. There are pros and cons to this, but a pro would be that one is introduced to these broader academic topics earlier on in a career, making it easier to transition through the ranks in academia, while also providing a broader skillset if leaving academia.
What is the difference between living in Lower Saxony and Wales?
The pace of life is much like South Wales, and the culture and humour are more familiar than in many other countries.
What do you miss about Great Britain?
Apart from the obvious deeper stuff like family and friends, a decent cup of tea, pub trips with colleagues on Friday after work, and discussions about the rugby.
